Edible sign. 1. A hand-held consumer product with chemical emanations that appeal to the senses of smell and taste. 2. A portable, fast-food symbol of the American way of life. 3. A mass-produced beef sandwich whose stratified layers mark an incredibly long prehistory in time.

Usage: The Big Mac "speaks" with a simple eloquence millions appreciate but few understand. Its meaty taste is enhanced by the rush of primarysalty, sour, and sweetingredients which address tongue receptors directly, but have little effect on more discerning nerves of the nose.

Prehistory. The Big Mac encodes a potpourri of flavor messages from the distant past. Because many of the sandwich's aroma and taste cues precede written history,The Nonverbal Dictionary excavated a Big Mac to decipher its chemical signs:

Layer I: Top bun. Harmonious flavor molecules released in cooking have made bread and meat an age-old combination. The first oven-cooked bread, invented by the Greeks, was eaten with opson (i.e., "non-bread" vegetables and meats) on top; the open-faced sandwich later evolved as pizza. (N.B.: According to a 2001 Parademagazine survey, conducted in the U.S., pizza is the favorite takeout meal and number-one food Americans say they "could not live without" [Hales 2001].) From the Dark Ages to the Renaissance, thick bread slices (or trenchers) were prepared with meat and sauce on top, paving the way for double-decker sandwiches, such as the Big Mac.

Layer I: Seeds. Sesame seeds on top had earlier spread from the Nile to the Orient, where they were mixed with wheat flour by pastry chefs for centuries. Roasted seeds add a nutty flavor, which appeals to the primate palate. Seeds provide tactile enjoyment for the tongue, as well (in reptiles the tongue evolved as a sensory organ for touch; see EXISTENTIAL CRUNCH).

Layers II & VIII: Meat. The browning reaction of cooked beef releases furans, pyrones, and other carbon, hydrogen, and oxygen molecules which provide the complex oniony, chocolaty, nutty, fruity, and caramel-like tastes we prefer to the bland taste of uncooked flesh (McGee 1990). At the heart of a Big Mac are two ground-beef patties, whose cooked flavor compounds would have been familiar to Homo erectus in Africa 1.6 m.y.a.

Layer III: Pickle horizon. Gherkins, eaten in India with salt or lemon juice for 3,000 years, came to Europe during the Renaissance. Along with their crunchy texture, pickles add a primary sour taste which has been enjoyed with lettuce since the Roman era.

Layers IV & X: Lettuce. A Big Mac contains 1/4 cup of chopped head-lettuce (Lactuca sativa), a plant preferred by the ancient Greeks above all other greens. Wild lettuce was prized for the soothing properties of its magnesium content, as an aid to digestion. Because of a burger's high fat content, our enteric nervous system considers lettuce a welcome ingredient today.

Layers V & XI: Onions. One-half teaspoon of finely diced onion, a root bulb, appears in each of two strata. An onion's volatile sulphur compounds evolved as warning messages to deter hungry grubs and insects (see SECONDARY PRODUCTS). Wild onions were used 4,000 years ago by Egyptian peasants to season bland meals, and Egyptian mummies sometimes included onions, wrapped in separate bandages, as carry-out for the afterlife.

Layers VI & XII: Sauce. Sauce adds moisture, required for the tongue to taste chemicals in solution. Sweet and sour sauces have flavored meats for thousands of years, and the Big Mac uses a variant of thousand-island dressing (made from salad oil, orange and lemon juice, minced onion, paprika, Worcestershire sauce (a spicy Indian recipe), dry mustard, parsley, and salt). The nonverbal secret of a Big Mac is the riddle of its sauce.

Layer IX: Cheese. A layer of American cheese lies above the lettuce horizon. Cuneiform tablets place cheese in the Near East by ca. 6,000 years ago. Cheese sends salty signals to the tongue tip, and its smoothness blends well with the coarser texture of beef. Flavorful fatty acids and esters of glycerol in cheese satisfy a natural craving for fat.

Neuro-notes. While the subtlety of cabernet, truffles, and haute cuisine is processed by higher brain centers, capable of culinary learning, the primary tastes of fast food are handled subcortically a. in the thalamus, and b. in a buried part of the cerebral cortex called the insula (which is emotionally linked to the amygdala and limbic system). Like primary colors, the basic bitter, salty, sour, and sweet tastes of fast-food coffee, fries, pickles, and soda make brash rather than subtle statements.